Water-tube boiler



All@ 5 A924, mmm@ A. COTTQN WATER TUBE BOILER Filed Dec. 8. 1,92!`

Patented Aug. lli, ltldi ALFRED COTTON, OF ST. LGUIS, DHSSOURI, ASSIG-NOR ST. LO'US, MISSOURI, A CORPORATION OF MSSGTURI.

isernia arent WATER-TUBE BQILER.

iippucanon ined December s, 1921. semi no. 520,371.

To all whom it may concern.-

Be it known that I, ALFRED COTTON, a citizen` of the'United States, residing at St. Louis, Missouri, have invented a certain new and useful Improvement in Water-Tube Boilers, of which the following is a full, clear, and exact description, suoli as will enable others skilled in the art to which it appertains to make land use the same.

This invention relates to water tube boil-` ers of the type that comprise a plurality of banks of upright water tubes connected at `their upper ends to transverse steamand-wuter drums.

It has for its main object to provide a highly eiiicient three bank boiler of such design that drier steam will be supplied than Iis possible with boilers of this general type now in use and which can be driven at a high rate without liability of causing the water level in tlie'rear steam-andwater drum to be lowered to such a point as to expose the upper ends of the tubes of the rearbanl, and thus cause the expanded joints between the upper ends of said tubes and the rear drum to leak, due to overheating of said joints. 4

To this end .l have devised a three bank, semi-vertical tube, transverse drum boiler, in which the water tubes at the front side oi' the first bank which are .exposed to radiant heat are connected at their upper ends to the front steamand-water drum, and the remaining tubes constituting more than half ot those in said first bank, and which depend mainly on convected heat, are connected at tliei. upper ends to the middle or seoond steuni-and-water drinn of the boiler, said iront and 'middle drums being connected together by water eiroulators of cross-sectional area approximating to that of those tubes of the first bank, which enter' the front drum. ln a boiler of the construction above desoribed, the upfl'ow of steam and water into the :iront drum. is considerably less than in conventional 'boilers of this general type now in use, owing to the fact that only the tubes at the front side of the first bank conduct steam and water into the .front drum. is less steam and water flows into the iront drum than the case in boilers of this general type,""and as the cross-seotional area oi the water ciroulators approximates to that of the tubes entering the Jiront drum, there is practically no tendency considerably, so that at for the water level to rise in 'the front drum, whereas, in lboilersoA this general type where the whole of the tubes in the first bank discharge into the roiit'drum and where the cross-sectional area of the water circulators is always less than one-half and often. less than one-third of the area of the tubes discharging into the front drum, the water level in the front drum rises very high loads it reaches to the steam circulators. This raising of the water level in conjunction with discharging the whole of the steam and water from the first bank into the front drum in conventional boilers causes the wa ter in the front drum to be. very tumultuous and to throw up a eonsiderable amount of spray which is carried over very readily, owing to the water level rising into close proximity with the steam circulators. The amount of water carried in suspension by the steam in any boiler is dependent upon the area of the steam disengaging surfaoe, which is that part of the surface'of the water where the steam leaves it. The smaller this surface is, the more tumultuous it is, and the more water is carri-ed away with thesteam, which is long and well known to engineers generally. In conventional boilers of this general type wherein the whole of the tubes of the iilrst bank discharge into the front steam-and water drum, the disengaging surface is the surface of the water inthe front drum only, since the steam disengaged in the otherA drums 'is quite negligible for all practical purposes." In a boiler embodying my invention, wherein a large proportion. of the steam and water flowing un the first bank is discharged into the middle drum, the sur face of the water in the middle drum is a disengaging surface .additional to that of the front drum. A. further inrease in the amount of disengaging surface is caused by avoiding the rise of water level in the front drum which takes place in conven- -tional boilers and which narrows the disengaging surface therein. The amount ot dis/engaging surface in my improved boiler is consequently about three times that of conventional boilers, and the water surface is therefore so much less tumultuous. The result is that drier steam will be supplied, as the water in the iront drum isoalmer than is usual in boilers of this general type dil.

an obvious fact, v

'and is not liable to rise to such a level as to'be carried over with the steam into the middle drum7 and as part of the steam -is disengaged from the Water in the middle drum, as well asin the front drum, the amount of disengaging surface is very much greater than in conventional boilers. Such a boiler as herein described can be driven at a high rate without causing` the water level in the rear drum to drop to such a point as to expose the expanded joints by which the upper ends of the tubes of the rear bank are secured to the rear drum, loecause the rise of water level in the front drum which causes a corresponding drop of the water level in the rear drum is very slight, as above mentioned. The disturbance of water levels is caused by the steam bubbles rising in the tubes of thelirst bank inducing an upward flow of water therein, so that any restriction of downward flow from the front drum to the mud drum raises the water level in `the front drum and lowers the pressure ih the mud drum, and the water level in the rear tube bank and drum falls until this lowered pressure in the mud drum is balanced. Accordingly, where the restrictions to circulation are removed. as in the boiler above described, the disturbance of water levels is reduced to a negligible amount in comparison to the objectionable disturbance of water levels tali; ingr place in boilers of conventional design ot' this general type.

The figure ot the drawings is a` vertical longitudinal, sectional view of a. boiler constructed in accordance with my invention.

Referring' to the drawings, A, B and C designate the front, middle and rear steamand-water drums ol my improved boiler, D designates a mud drum and E, F and G designate front, middle and rear banks of upright Water tubes. The tubes at the front side of the front benl; E which are exposed to radiant heat, consisting of the rst two or three transverse rows of tubes, have their upper ends connected to the front steamanc`1-water drum il. The remaining tubes o" said front bunk. consisting of the tubes which depend mainly on couvected heat, have their upper ends con uected to the middlc steam-:uidwater drum B. 'The tubes ot' the middle baul( F which act as downcomers are connected at their upper ends to the middle drum ll and the tubes of the third bank o1' ccouoinizer bank (l are con nected at their,n upper ends vto the rear steam-rind-water drum C. Steam circulators l and water circulators 2 are provided for connecting the steam-andwater drums together, und the rear drum C is provided with a steam outlet 3 and a feed water inlet et. The baiilingr comprises a first baille 5 arrai'zkged transversely of the boiler at recessie@ rear side ofthe front tube bank E with its lower end terminating at the "mud drum D and its upper end spaced away from the 'banks in the manner indicated by the arrows and escape through an youtlet 7 at the upper end of the boiler setting.

When the boiler is in operation part of 'the water that flows upwardly through the tubes of the front bank E enters the front steameindwvater drum A, .and the remainder of the water that Hows upwardly through said front bank enters the second drum or middle drum B,l the walter that enters the front drum A escaping from same into the middle drum B?. through' the water eircu lators 2 between said drums, which are prefere/bly of such crosssectional area as to insure a free and rapid escape of the water from the front drum into the middle drum. All of the waterthat enters the middle' drum B Hows' downwardly through the downcomer tubes constituting the middle bank F to the mud drum D. By constructing the boiler in such a manner that only part of the Water which flows upwardly through the iront bank enters the front drum A, the resistance to circulation is materially reduced. as a large proportion of the water that flows upwardly through the Jfront benk enters the middle drum B and flows transversely across same to the downcomers F without having to encounter the resistance to flow of any Water circulators. Consetulently,v the water in the front drum will be much calmer than is usual in boilers of this general type, even when the boiler is driven at a high rate, and is not liable to rise to su'ch a level as to be carried over with the steam into the middle drum, thus insuring the production oi'drier steam lin the front-*drum A of the boiler. More` over, such a boiler can be driven at a high rate without liability of causing the Water level in the rear drum dropping to such un errent as to uncover the expanded joint-s between the upper ends of the tubes ofthe rear :bank and the rear drum, due to the 'inet that a large proportion of (or more than half ofl the tubes ofthe front bank are connected to the second steam-and-water drum in such a manner that there is no tendency for the Water to accumulate in the front drunn due to restriction 'of circulation, as frequently occurs in conventional boilers of this general type, wherein all of the water flowing upwardly'through the front Ibank passes' through the front drum before entering the. middle drum.

Lacasse Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

drums arranged one in front ofv the other, a transverse mud drum, a front bank of water tubes combined with said mud drum ire gases to fiow upwardly over said and said elevated drums in such a manner that the tubes that are ,subjected mainly to convected heat and which are directly connected at their upper ends to the second elevated drum oiier the major cross-sectional area of pathto the water which circulates upwardly through said bank and the remainder of the tubesat the iront side of said bank which are exposed to radiant heat and which have their upper ends connected to the front drum oder the minor cross-sectional area of path to said upwardly circulating water, water circulators that connect the front drum with the second drum, downcomer tubes that lead from said second drum to the mud drum, and means for causin the ont bank and downwardly over said do'wncol'ner tubes.

2. A water tube `boiler provided with a first and a second transverse steam-andwater drum, a transverse mud drum, a front bank of water tubes connected at their lower ends tosaid mud drum and comprising a relatively few radiant heat tubes whose up r ends are connected to the first drum an a greater number of convected heat tubes 3. A water tube boiler comprising three elevated transverse steam-and-water drums, a transverse mud drum, a front bank of water tubes comprising a vfew transverse rows of tubes at the iront sidec said bank connected at their upper ends to the front steam-and-water drum and a greater number of transverse rows of tubes 'ebunected at their upper ends tothe middle drum,a iniddle bank of downcomer tubes connected at their upper ends to said middle drum, a rea-r bank or economizer bank 'of tubes connected at their upper ends to the rear drum, steamand-water circulators between said steamand-water of each bank being connected to the mud drum and the water circulators between the front and middle drums being of approximately theV same cross-sectional area as the drums, 'the lower ends of the tubes tubes at the front side of the irst bank whose upper ends are connected to said front steam-and-water drum, and baliles arranged to cause the gases to flow u wardly over said front bank and downward y over said middle bank.

4. A water tube boiler, comprising three elevated steam-and-water drums, a mud drum, an economizer bank of tubes that `connects the rear drum with the mud drum, a downcomer bank of tubesthat connect the middle drum with the mud drum, a front bank of upfiow tubes composed of a few `txansverse rows of tubes at the front side o said front bank which connect the mud drum with the front steam-and-water drum and a greater number of transverse rows of tubes y that connect the mud drum with the middle steam-and-water drum, steam and water circulators between said steam-and-water drums, and bames for causing the gases to ow upwardly over the front bank, down--` wardly over the downcomer bank and upwardly over the eccnomizer bank.

j ALFRED correu. 

